I got one of those as well. And it came after attempting to fight someone and getting a server error (that I've never gotten before). I'm quite sure I was only fighting one at a time. I'm no fast click click clicker!

I get this when I fight a high evasion minion. I think when the character is switching gears the program lags on calculating the evasion level and therefore your fighting gets lagged. Eventually it things your fighting 2 battles if you hit "fight" again.

it just now took me 1 minute and 20 seconds from the time i hit the train link to the time it refreshed and was finished. the time is increasing for me quite dramatically. i am going to train every second and see if i can bring cb to its knees!

To allow everyone fair access to the limited cpu resources, each user may only be in one fight at a time.

If you clicked on fight before your last one finished, you will get this error. Remember, 'your last one' could have been a challenge page, so moving to another activity is NOT safe at this point.

This is open to abuse since it's so easy to create new user accounts. Creating multiple user accounts is illegal, but rather than make that process more onerous for legitimate new users (such as by email verification, which in any case is trivial to spoof), we've chosen as the most foolproof method to additionally limit fighting on an IP address basis for non-Supporters. This means that if you're behind a firewall that makes multiple computers appear to share the same IP, your fights will conflict with others from behind your firewall.

I have huge Evasion and fight high Evasion characters -- I rarely have the fight timeouts... It does happen sometime, but I usually find it is something on my end...

Are we sure this is reproducible back to Evasion? Maybe Evasion on targets doesn't affect me since I am all magic damage, but I am not sure the game would forego the Evasion calculation by knowing to look at the opponent and see they have nothing physical attacking...

Third gives me:
To allow everyone fair access to the limited cpu resources, each user may only be in one fight at a time.

If you clicked on fight before your last one finished, you will get this error. Remember, 'your last one' could have been a challenge page, so moving to another activity is NOT safe at this point.

This is open to abuse since it's so easy to create new user accounts. Creating multiple user accounts is illegal, but rather than make that process more onerous for legitimate new users (such as by email verification, which in any case is trivial to spoof), we've chosen as the most foolproof method to additionally limit fighting on an IP address basis for non-Supporters. This means that if you're behind a firewall that makes multiple computers appear to share the same IP, your fights will conflict with others from behind your firewall.

Fourth gives me:
Didn't I say it's not polite to fight more than one battle at a time? You'll have to wait about 10 minutes now for fight to be reenabled.